Multi-Epoch GNSS Campaigns of the National Geodetic Network in Estonia

The measurements of the EUREF (IAG Regional Reference Frame Sub-Commission for Europe) densification in Estonia were conducted in the summer of 1997. The network has since been remeasured twice (in 2008 and 2017), including also available national GNSS reference stations. In the present study all three campaigns have been recomputed and the results are expressed in the latest International Terrestrial Reference Frame ITRF2014 (ITRF, 2019). As a result, the coordinates of the Ist order geodetic points were specified. The RMS errors of the individual coordinate components with respect to the average of the three campaigns were 1.9 mm, 2.9 mm and 2.8 mm for north, east and up components, respectively. Also, the velocity estimates for the points were estimated and compared to corresponding regional velocity models. The discrepancies (in terms of standard deviation) with land uplift model NKG2005LU were in average 0.2 mm/year only. The resulting horizontal velocities however are subject to further research.